This invention relates to an improved roll-up truck cover assembly of the type wherein a flexible cover is secured at one end of a take-up roll mounted to a pair of swinging arms, one on each side of the truck body, for moving the cover from an open to a closed position over the top opening of the truck to cover a material load, such as gravel or loose dirt. The cover assembly is further adapted to move the cover in an opposite direction to an open position when the load is to be removed. Typically, the swinging arms are made up of two pipes clamped and bolted together to form a one arm unit on each side of the roll-up cover assembly to extend the cover completely over the load from one to an opposite end of truck body. The swinging arms are driven or swung by hydraulic or fluid operated cylinders.
Roll-up cover assemblies of the type described above are disclosed, for example, in U.S. Pat. Nos. 4,050,734 and 4,341,416 issued to D. B. Richard on Sep. 27, 1977 and Jul. 27, 1982, respectively, the specifications of which are incorporated herein by reference for purposes of background information.
The problem with roll-up truck cover assemblies of the above type is that in order to dispense the cover from the take-up roll over the entire length of the top opening of the truck body and then to move the cover in an opposite direction, it is necessary to rotate the swinging arms in an arch-like fashion to a maximum height at a point somewhere midway along the length of the truck body. Unfortunately, this action in some cases results in the take-up roll and/or cover striking a local over-hanging object, such as a tree branch, for example, or in more hazardous cases, over-hanging electrical transmission wires or cables. This is particularly true in cases where larger and longer trucks, such as a trailers are employed, which in turn require larger and longer covers, as well as longer and taller swinging arms to move the cover.
It is therefore an important object of this invention to provide an improved roll-up truck cover assembly wherein the take-up roll and cover travel over an arch-like path in which the maximum height of the roll and cover above the top opening of the truck body is kept to a minimum or, stated in other words, in which the roll and cover travel in a lower arch-like or more horizontal path over the top opening than has been heretofore possible with similar truck cover assemblies of the prior art.